Lecture by Akash Koppa about his new Science paper: 18.9. at 14:00 in D216

[oldrich rakovec]

Dear colleagues,

We would like to invite you to a presentation by Akash Koppa on Land–Atmosphere Feedback as a Mechanism of Dryland Expansion, on Wednesday 18th September at 14:00 in D216 (MCEV-II building), in Prague 6 Suchdol (ČZU campus).

Akash Koppa is a hydrologist and civil engineer by training, who primarily works on large scale hydrology, high-resolution atmosphere and land surface modeling. He led a very recent Science paper, he is currently working at EPFL (Switzerland) and previously at the Ghent University (Belgium) and UFZ (Germany).

Abstract of his talk: Just in the last four decades, ~5 million sq.km of humid land has transformed into a dryland. A rapidly warming climate is expected to further accelerate this dryland expansion. Consequently, societies which have surplus water could face permanent water insecurity in the future. However, very little is known about the physical mechanisms which cause irreversible long-term drying of humid regions. So far, dryland formation has been attributed to shifts in large-scale atmospheric circulation and increased radiative heating through changes in orbital cycles.  Here, I show, using atmospheric transport models, that land–atmosphere feedbacks play an important role in dryland expansion. As they dry, drylands contribute less moisture and more heat to downwind humid regions, reducing precipitation and increasing atmospheric water demand, which ultimately causes their aridification. Furthermore, I show that this self-expansion process is prevalent in all major drylands across the globe. These results provide a scientific basis for developing targeted conservation and adaptation measures against dryland expansion.

Reference: https://www.science.org/doi/10.1126/science.adn6833 

Looking forward to seeing you there. 

Best regards, 
Oldrich Rakovec